4o6 BOTANY AND PHARMACOGNOSY. 



which have been grown from cuttings of rhizomes are licorice 

 and ginger, but it is likely that all plants which produce rhizomes 

 can be readily propagated from cuttings. Cuttings of over- 

 ground stems are made from the growing parts of branches, 

 and it is necessary to have them of such a length that at least one 

 node may be placed in the soil. These are at first planted in 

 micaceous soil or river sand, which should be kept well moistened. 

 It is desirable that the leaves be as few as possible, so as to reduce 

 the transpiring surface until the young roots have been formed, 

 which may take several weeks or several months. Usually the 

 lower leaves should be cut off entirely, while the others may be 

 partially trimmed. The cuttings should also be protected from 

 strong light, as this tends to increase transpiration, and also 

 against a dry atmosphere, which may be accomplished by cover- 

 ing them with glass, particularly during the day, when the 

 weather is dry. Cuttings of hard wood plants intended for out- 

 door culture should be made in the fall. They should be 6 or 8 

 inches in length, kept covered with sand in a suitable place during 

 the winter, and planted in the spring. 



One of the methods for producing new varieties is by hybrid- 

 ization, or cross-pollination, of different related species or varie- 

 ties. The offspring is known as a hybrid, and has a blending of 

 the qualities or characters of the two parent plants. This method 

 is mostly employed by florists who desire to produce some new 

 or striking flower, or by horticulturists who desire to establish 

 some new quality or transfer a desirable quality from a foreign 

 plant to one which is adapted to a given locality. The method 

 has not been largely employed in the cultivation of medicinal 

 plants, except in the case of cinchona, where it is claimed that the 

 barks richest in alkaloids are the direct result of hybridization 

 and selection. By transplanting and special methods of treatment, 

 as that of mossing, the alkaloidal percentage has been increased 

 from 8 per cent, to lo, whereas by hybridization the amount of 

 total alkaloids has reached as high as i6 per cent., about three- 

 fourths being quinine. 



THE COLLECTION, CURING AND YIELD OF DRUGS. 

 On page 418 are given some general rules for the collection of 

 vegetable drugs, and attention is directed to the importance of 



